3.9 GHz System (AH1) XFEL WP46

Transcription

1 3.9 GHz System (AH1) XFEL WP46 14th European XFEL Machine Advisory Committee Meeting 02 May 2016 Paolo Pierini, INFN & DESY Elmar Vogel, DESY + INFN/DESY contributors PPT version 1 26/04/2016

2 Outline Status presented at Nov 2015 MAC Operational experience during injector commissioning Spare module preparation Plans for R&D at CW for upgrades

3 WP46: 3.9 GHz System STATUS PRESENTED AT LAST MAC

4 Status at 13 th MAC (11/15) and report Module installed & visited by MAC in the Injector Waiting for first cooldown and RF characterization 1 cavity tested with tuner, magshield, coupler at AMTF MAC Report As the 3.9 GHz module has not been tested before installation, maybe some extra commissioning time needs to be scheduled. The commissioning team is well aware that the 3.9 GHz module has not been tested before installation. It is very appropriate to cool down as soon as possible to find out if any problem exists with this and other parts of the beamline.

5 WP46: 3.9 GHz System MODULE ASSEMBLY AND INSTALLATION

6 Timeplan presented at 12 th MAC Meeting Cavity Preparation CR String Assembly (2 Wks) Module Assembly (7 Wks) Installation, technical commissioning (8 Wks) P. Pierini, 14th XFEL MAC Meeting 12 th MAC 02/May/2016

7 14 weeks from cavities to tunnel Status and plans for the 3.9 GHz section of XFEL Module assembly timeline Where When Activity CLEAN ROOM (3 wks) ROLL-OUT AREA ON GIRDER (2 wks) ROLL-OUT AREA SUSPENDED (2 wks) CANTILEVER (4 wks) FLOOR SUPPORT (3 wks) WK25 WK26 WK27 WK28 WK29 WK30 WK31 WK32 WK33 WK34 WK35 WK36 WK37 WK38 WK39 Clean room preparation, last coupler installed on cavities String installation start. Cavity connections Finish installation. String Roll-out Partial magnetic shield installation and tuner installation, T sensors 2 phase line welds, T sensor installation completion, tuner motor Suspension from cold mass, completion of magnetic shield, alignment End of string alignment (2 pass and final survey), transfer to cantilever, preparation of 2K thermal sinking (HOM, motor), HOM notch filter tuning Weld of the magnet package current leads, weld of the warmup circuit RF cables, completion mag shield, HOM thermal sinks, installation of coupler cones, cable thermalization, start assembly of 4K shield parts Finalization of 4K/80K shields and MLI blankets Vessel roll-on, post bracket/suspension of the Cold Mass on the Vacuum Vessel, longitudinal pre-alignment of CM to VV, transfer to floor supports CM to VV alignment, start of coupler installation Finish coupler installation on one side, install coupler vacuum pump line Coupler side two, coupler vacuum, beam vacuum & leak check Transport to Tunnel

8 Major Assembly Milestones July September

9 Activities in between

10 Final Preparation stages in tunnel November th MAC Assembly WG distribution Injector String Integration Dec 10: Start cooldown Dec 15, cavity pre-tuning Dec 16, calibration: AH1 Ready 50 kw LLRF & Klystron calibration on load

11 WP46: 3.9 GHz System MODULE RF COMMISSIONING

12 Cavity vertical tests at INFN/LASA First cavity vertical test 26-Sep-14 and last 11-Feb-2015

13 RF Commissioning in Tunnel Infrastructure aspects, workload of main linac module testing activities and schedule delays made it impossible to perform an integral test of the module before tunnel installation The module was installed in tunnel without cryogenic and RF testing Tunnel environment is not the most favorable for precise RF measurements activities Few RF power meters with respect to AMTF, though a few not initially foreseen were implemented (e.g. HOM power readings, not preent in the main linac) The positive aspect is that all subcomponents were in their final configuration and driven by the XFEL control system Smooth transition from characterization to operation

14 Main characterization checklist Cavity performances, up to quench limit - done Phase alignment and QL tuning - done Beam-based calibrations - done HOM thermal stability studies - done Cryogenic performance assessment - done Preserving (and improving) beam quality ongoing Characterization of the RF power distribution skipped (for schedule reason)

15 First operation at nominal gradient on Day 1 18 December 2015 Operation with no beam First rough calibration Nominal pulse structure Fill Time: 750 us Flat Top: 650 us Gradient well above nominal 40 MV of VS voltage First quench > 45 MV Cavity phasing missing and QL values not yet tuned LLRF in FB mode

16 Beam Based calibration: Cavity Phases Cavity transient, QL determination and phase calibration January 2016, on beam Beam transients Phase Calibrations Preliminary to : Phase Tuning QL tuning Large initial cavity phase spread WG assembled in tunnel, no cal. 160 Beam induced cavity gradient changes After operation of a few stub tuners Tune with 3-stub tuners WG Spacers

17 QL tuning & Phase alignment 1 February 2016, AH1 moved 1 ms after the beam Allow injector commissioning while aligning cavity phases Individual maps of 3-stub tuner positions QL-Phase region Case of design in range of tuner QL-Phase region Case of design outside range of tuner WG spacers installed on 3 cavities

18 Started regular operation in injector 10 February 2016 QL aligned well within the 10% requirement Phases within February 2016 Back on beam Moved to -180 (wrt on-crest), calibration with beam energy

19 Quench Gradients & HOM performance Cavity Q0 is 2E9 (VT measure) Qt is 1E10 (VT calib) Cav QH1 QH2 C1 7.29E E+11 C2 1.14E E+10 C3 8.70E E+11 C4 1.91E E+11 C5 3.18E E+11 C6 8.32E E+11 C7 1.36E E+10 C8 4.50E E+15 C1 HOM1 suboptimal tuning C4 HOM1 detuned (cavity Q0) Stable thermal behavior Cav Max Gradient Tunnel Limit VT Gradient C MV/m Quench 21.0 MV/m C MV/m Power 20.0 MV/m C MV/m Quench 20.8 MV/m C Mv/m Power 22.0 MV/m C Mv/m Quench 21.0 MV/m C Mv/m Power 19.6 MV/m C Mv/m Quench 20.0 MV/m C Mv/m Power 21.8 MV/m Tunnel measurement much less accurate WG distribution assumed uniform (3x3dB+loss)

20 Temperature stability at highest SP In spite of the large peak fundamental mode power leaking out of two HOM1 couplers temperatures are extremely stable Levels at 20 MV Three CERNOX sensors are at each HOM can end (flange, tophat and inner antenna base) and connected to technical interlock system 40 MV Never triggered

21 Cryogenic aspects Static loads of individual component in the injector circuit cannot be individually assessed, only global measurements can be done Including end and feed box and both modules However, using data from components assessed in AMTF MKS estimates 2 K: 4-7 W 5/8 K: N/A problems with flowmeters 40/80 K: approx 95 W Overall, performance similar to 1.3 GHz modules Somewhat expected, same concept, same # penetrations Well within capabilities of cryocapabilities at injector

22 First confirmation of linearization effect TDS diagnostic not yet available at injector 12 April 2015 transmission of full train with acceptable losses in the after last dipole to beam dump not possible without AH1 AH1=0 MV AH1=10 MV

23 WP46: 3.9 GHz System SPARE INJECTOR MODULE PLANS

24 Spares components 5 cavities for spare module presently at DESY 2 from previous series production 3 from the second series of 10 cavities 5 more cavities tested, expected before end May/mid June Last 2 cavities of the second series delayed Vessel integration non-conformities: Repair Module (CM and VV) at DESY Several other components already have been procured in quantities for 2 modules and are already in stock either at DESY, INFN or FNAL Couplers, magnet, magnetic shields, PU and HOMs, beam line flange transitions, vacuum line, waveguides, etc.

25 Spare module activities String assembly and module installation scheduled to start in September, after tunnel closure and DESY Clean Room maintenance Increased manpower availability for all operations with the end of tunnel assemblies Adaptation of the module support rail for XATB1 in AMTF ongoing (BINP procurement) Ready before end of 2016 Testing in nominal XFEL pulsed conditions in early 2017 XATB1 already equipped with RF (single cavity tests) Planning ongoing for tests in CW performances Two companies exploring 3.9 GHz 1 kw

26 WP46: 3.9 GHz System CONCLUSIONS

27 Summary RF commissioning of the 3.9 GHz module in the tunnel was a great success Achieved performances above nominal during the early injector commissioning stages in December 2015, with the AH1 pulse shifted in time from the beam Module in regular operation with beam since January 2016 Final verification will be achieved with TDS The second spare module is well proceeding towards assembly & testing An extended test scope for CW testing with SSA is being discussed, in view of the possible future high duty cycle upgrades of the XFEL facility

28 WP46: 3.9 GHz System THANKS! Acknowledgements INFN M.Bertucci, M. Bonezzi, A.Bosotti, JF.Chen, M.Chiodini, M.Fusetti, C.Maiano, P.Michelato, L.Monaco, M.Moretti, C.Pagani, R.Paparella, D. Sertore DESY Too many people from MIN, MKS 1, MKS 3, MHF-SL, MPL, MSK, etc. And especially the whole BKR team FNAL Elvin Harms and the ACC39 team Most photos courtesy of D. Nölle/Ettore Zanon S.p.A.

29 After final round of Beam Based Calibration After LLRF final calibration with beam induced transients an asymmetry of the WG distribution is apparent (left/right arms of the distribution system Confirmation requires dedicated measurements of WG distribution at high power Directional Couplers) Odd-numbered Even-numbered Regular closed loop operation, at 20 MV setpoint Requires RF cables disconnection to LLRF panel & several accessess with measurement equipment Did not proceed as module performances are reached with margins!